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| FOR IMMEDIATE RELEASE Sept. 20, 2003, 2:15 p.m. EDT |
For more information, please contact the ATA at thyroid@thyroid.org. |
Irregular Heartbeat is Common Side Effect of
Over-Active Thyroid,
Resists Treatment Leading to Death
(PALM BEACH, FLA., Sept. 20, 2003 ) - An irregular heartbeat, called atrial
fibrillation (AF), affects almost 10 percent of those with an over-active
thyroid, known as hyperthyroidism, and this problem often continues despite
effective treatment of the thyroid condition, according to a new study
being presented today at the 75th Annual Meeting of the American Thyroid
Association.
The study also found that hyperthyroid-induced AF is of particular concern
for elderly males. Furthermore, this complication of the thyroid condition
is associated with an increased risk of death.
"Physicians need to have a heightened awareness that this is a serious
complication of hyperthyroidism," advised Jayne A. Franklyn, MD,
PhD, senior author and professor of medicine in the Division of Medical
Sciences at the University of Birmingham and Queen Elizabeth Hospital
in Edgbaston, Birmingham, United Kingdom. "In turn, this should prompt
rapid treatment and specialist referral of patients with hyperthyroidism,
preferably before development of atrial fibrillation."
Dr. Franklyn and colleagues had previously found that there is increased
risk of death from cardiovascular diseases in patients with previous hyperthyroidism.
Therefore, they wanted to investigate the issue further.
The researchers recruited 425 patients with overt hyperthyroidism, which
can result in an increased metabolic rate, enlargement of the thyroid
gland, rapid heart rate, and high blood pressure. Dr. Franklyn noted that
the majority of all hyperthyroid patients have a rapid heart rate before
thyroid treatment because excess thyroid hormones speed up the heart.
Of the total group, 334 were female and 91 were male, with 35 of the group
(8.2 percent) being diagnosed with AF.
Of those with AF, their average age was 71 years old, and men were over-represented
in the group at 11. Ten of them had known AF, 20 newly onset AF, and five
had sudden, temporary episodes of AF, known as paroxysmal AF, before and
after thyroid treatment. All but two of the 35 patients were treated with
anti-thyroid thionamides and radioactive iodine. Two returned to normal
thyroid function immediately, and four died during the follow-up period.
Only 10 of the patients returned to a normal heart rhythm, either due
to thyroid or heart-related treatment, the latter composed of drugs or
electrical cardioversion.
"More effective means of managing those with this complication need
to be developed," added Dr. Franklyn. "This might mean earlier
intervention with drugs in an attempt to abolish the abnormal rhythm or
development of new electrical methods to achieve a normal rhythm."
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